Turbulent climate

Yingluck on Thursday voiced fears the protesters aimed to use violence and to "overthrow an elected government and democratic rule", in a televised address to the nation.

The government has invoked a special security law, the Internal Security Act (ISA), in three districts of the capital to cope with possible unrest.

"We will evaluate the situation daily and if it escalates we are ready to invoke emergency rule, but so far I think the ISA will be sufficient," Thai police chief, General Adul Sangsingkaew, said on national television.

Politically turbulent Thailand has been rocked by a series of sometimes violent rival street protests in recent years, although an uneasy calm has returned after national elections in 2011.

Two months of mass opposition protests in 2010 by "Red Shirt" supporters of ousted premier Thaksin Shinawatra sparked a deadly military crackdown that left about 90 people dead and nearly 1900 wounded.

Mr Thaksin's sister Yingluck is now prime minister after his political allies won a landslide election victory last year.

Mr Thaksin, who made billions as a telecoms tycoon, is adored by many poor Thais for his populist policies while in power, but reviled by many in elite, military and palace circles who see him as authoritarian and a threat to the monarchy.

"This government ignores widespread disrespect of the monarchy and even supports the perpetrators. It is a puppet of Thaksin," Pitak Siam spokesman, Vachara Riddhagni, said ahead of the demo.

Observers say prosecutions for insulting the monarchy have surged since royalist generals toppled Thaksin in a coup in 2006. Many of those targeted are linked to the Red Shirt movement.

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